Are there any specifics on the rules/restrictions of the Ritz certs? Or do you just call them and they say "no", a la those commercials?

In general, my wife and I avoid traveling to cities when there is peak hotel demand unless we are specifically attending the event that is causing all of the demand. We like visiting popular destinations at off-peak times - mainly to avoid the tourist throngs, but also because it's easier to get travel awards if we want 'em. So if using these free Ritz-nights is simply on-par (in terms of difficulty) with redeeming Marriott points for the same room, I'd probably be OK with it.